Ultra-short-wave tube



Dea. 20, 1938- w. DLLENBACH 2,141,080

f ULTRA-SHORT wAvE TUBEl Filed Aug. 18, 1956 '2 sheets-sheet 1 Dec. 2o, 193s. wf DLLNBAC-H 2,141,080

LTRA- SHORT WAVE TUBE Filed Aug. 18, 1956, 2 Sheets-Sheet .2

Patented Dec. 20, 1938 UNITED STATES PATENT OFFICE ULTRA-sHonT-WAVE TUBE Application August 18, 1936, Serial No. 96,689

In Germany August 19, 1935 4 Claims.

According to the invention there is proposed, 'for the production of ultra-high-frequency electro-magnetic oscillations, an electron tube with a chamber as a resonator which is bounded by an internal conductor and a coi-axial external conductor and the internal conductor of which is provided with a grid and in the interior of the grid with a co-axial cathode, whilst, for the purpose of producing a large iiywheel resistance of l the resonator, the distance between the internal and external conductors. is made largeV and is reduced only at the part serving for the exciting.

By iiywheel resistance is to be understood the expression Z2; Z being the wave-resistance of a 35 Lecher conductor, namely the ratio (self induction) C capacity The reduction of the distance apart inthe chamber serving for exciting can be effected in twov ways: in the rst place by the increase of the diameter of the grid; and further by the provision of a pole-shoe-like Vannular body on the side of the external conductor that is turned towards the grid.

By the great distance apart of the co--axial conductors, a small natural damping is produced. A further advantage exists in that by the relatively large surface the load capacity of the grid is increased, which is specially advantageous in the case of the employment of the tube in braking-field connection with agrid having a highly positive bias in relation to the cathode. Furthermore, by the disc-shaped wall parts which are connected to the grid electrode and which serve for connecting the grid with the internal conductor there is produced a favourable conducting away or radiation of heat; Also, on account of the relatively large grid diameter, small dissymmetries at the cathode are less injurious to the exciting conditions of the tube. In both cases, the tube is shorter which results in a considerable reduction of the ohmic resistance of the resonator and a shortening of the path for the leading away of the heat.

The invention is illustrated in the accompanying drawings, in which:

Figure 1 is a longitudinal section of one form of the invention. Figure 2 is a section on line 2 2 of Figure 1.

Figure 3 is a vertical section of another form of the invention.

Figure 4 is a section on line 4-4 of Figure 3. Figure 1 shows in longitudinal section and Figure 2 in cross section a tube, which corresponds substantially to a constructional example of application 43,788, with the characteristics according to the invention. The hollow body surrounding the resonator consists'essentially of the cylindrical external conductor I and the concentric 5 internal conductor 2, 2 consisting of two sections. At the lower end the external and internal conductors are galvanically connected together by the circular annular disc 3. The upper end of the external conductor is galvanically connected l0 through the circular annular disc 4 with the hol'- low cylinder 5, which forms the external conductor of a concentric high-frequency conducting device. The section 2 of the internal'conductor is pro-longed, without variation of cross 15 section, by the internal conductor 6 of the highfrequency conducting device, which merges at its upper end into the rod antenna 1. To the upper end of the external conductor 5 there is connected, at right-angles to the axis of the tube, a 20 metal plate 8, which serves for the capacitive transmission ci the antenna current to the external conductor. At a short distance from and within the external conductor I of the resonator there is a cylindrical electrode 9, which is sup- 25 ported in the vessel-like hollow body I, 3, 4 by means of insulators I0. This completely enclosed. electrode 9 can be given a special bias by means of a lead I I that extends through the externa conductor and is insulated therefrom. 30

In contradistinction to the corresponding tube represented in application 43,788, the distance between the internal conductor 2, 2 and the external conductor I or the enclosed electrode 9 is made great sorthat the resonator presents a 35 large wave resistance. The. middle portion of the internal conductor, which is formed as a cylindrical grid I2, is made with a relatively large diameter so that a small distance apart, favourable for exciting, is maintained between the grid 40 and the electrode 9. The wave resistance of the resonator is consequently small only at this place. For connecting the grid with section 2, 2 of the internal conductor there serve the flange-shaped projections I3, I3. Co-axially with and in the 45 interior of the grid there is a hairpin-shaped cathode I4, which is stressed by meansl of the helical spring I5 through the tension wire I 6. The helical spring and the tension wire are 1ocated within the insulating body I1 and within 50 the hollow internal conductor 2 as well as 6. The leads I8 pertaining to the cathode are introduced into the interior of the tube through and insulated from the portion of the internal conductor 2', which is likewise made hollow. The lower end Q tenna.

of the conductor 2' projects out somewhat beyond the plate 3 and is provided with a short glass tube I9, which closes the interior of the tube in a vacuum-tight manner. Other vacuum.- tight glass fusion joints 20, 2| are located at the place of introduction of the lead II and at the upper end of the high-frequency conducting device.

The tube serves preferably for the production of oscillations in the braking-held connection, in the case of which the external and internal conductors and consequently the grid receive a highly positive, and the completely enclosed electrode 9, a weakly positive or negative potential in relation to the cathode. For the purpose of preventing the two flanges I3, I3' which connect the grid with the two sections of the internal conductor, from receiving emission they are covered by discs 22, 22', which are connected in the present case with the cathode. In the case of an insulated arrangement of these discs they may be given a negative potential in relation to the cathode.

The mode of operation of the tube is in principle the same as follows: The exciting chamber, the grid I2 and the electrode S serves as a concentrated capacity, and the eld chambers adjoining the two ends serve as self-inductances. On account of the cylindrical or disc-like formation of the conductors bounding the two self-inductances, these have a rectangular prole in longitudinal section. Now on the production ci oscillations there are formed a potential antinode of the oscillation in the exciting chamber between I2 and 9 and potential nodes of the oscillation in the neighbourhood of the place where the disc 3 is connected with the internal conductor 2 and at the place where the resonator chamber merges into the high-frequency conducting device 5, 6. The chamber between the electrode 9 and the external conductor I acts as a short-circuit condenser that is dissonant in relation to the natural frequency. The length of the high frequency conducting device is, just as in the case of the tube of application 8,938 in the most favourable case M4- or an odd multiple thereof, so that a potential anti-node of the oscillation is formed at the place of transference between the en-ergy-conducting device and the an- In this case also an optimum suiting of the antenna resistance to the resonator can be produced by the suitable choice oi the distance between the conductors 5 and On account of the special formation of the resonator, its length is not equal to M2, as in the case of the corresponding tube oi application 43,788, but is shorter, so that the ohmic resistance of the resonator is reduced and the path for conducting away the heat is shortened.

Figures 3 and 4 show in longitudinal section and in cross section a tube corresponding to the second constructional form. The difference in comparison with the tubes represented in Figures 1 and 2 consists only in that the internal conductor of the resonator is provided with a grid of the same diameter and the cylindrical electrode 9 is provided on the side turned towards the grid with a pole-shoe-like annular body 23, by means of which the distance between the grid and the braking electrode is reduced. The advantages of the first constructional form are present in this case also. In particular, by the shortening of the internal conductor the ohmic resistance of the resonator and the resistance to the conducting away of heat are considerably reduced.

What I claim is:

l. An electron tube for ultra-high-frequency electromagnetic waves comprising a resonator formed as a hollow body substantially closed on all sides against radiation loss and defined in part by an internal conductor and a coaxial external conductor, a grid connected to said internal conductor, and a cathode disposed in the interior of the grid, the distance between the grid and external conductor being less than the distance between the internal and external conductors. Y

2. An electron tube for ultra-high-frequency electromagnetic waves comprising a resonator formed as a hollow body substantially closed on all sides arid defined in part by an internal conductor and a coaxial external conductor, a grid concentric with and connected to said internal conductor, andra cathode disposed in the interior oi the grid, the diameter of the grid being larger than the diameter of the internal conductor.

3. An electron tube for ultra-high-requency electromagnetic waves comprising a resonator formed as a hollow body substantially closed on all sides and defined in part by an internal conductor and a co-axial external conductor, a grid concentric with and connected to said internal conductor, and a cathode disposed'in the interior of the grid, the distance between the grid and external conductor being less than the distance between the internal and external conductors, the conductors Vdening the resonatoi` being cylindiically shaped7 the area of the internal conductor confining the grid-cathode space being covered by discs.

4. An electron tube for exciting ultra high irequency electro-magnetic oscillations, comprising a resonator formed as a. hollow body substantially closed on all sides and dened in part by an internal conductor and a coaxial external conductor, a grid connected to said internal conductor, a plate surrounded by said external conductor, and a cathode disposed in the interior of the grid, the distance between the grid and external conductor being less than the distance between the internal and external conductors serving as electrodes.

WALTER DLLENBACH.

Cil 

